Which feed form is better to control gut health – pellet or coarse?
Our Expert: Dr. E. Nancy Fischer, Senior Nutritionist, Country Junction Feeds
Answer
For the most part pellets or crumbles improve broiler performance over mash and the cost is easily justified. The feed is consumed as a uniform mix with the bird getting everything it needs in a single bite. The feed is easily digested, from both a starch/energy utilization standpoint and from an amino acid digestibility standpoint. Some have gone so far as to show the energy saved by the bird consuming pellets vs mash can be as high as 187 kcal/kg of feed and this energy can therefore be more available to the bird for better support of its immune system (Mckinney and Teeter, 2004). The feed is easier to handle, has a higher bulk density, has limited ingredient segregation as well as improved feed flow. The better the pellet quality, the bigger the improvement in performance (Glover et al, 2018; Moritz et al, 2001).
But what about gut health? If a bird is performing well, isn’t that proof of a healthy gut? It is one indicator, but susceptibility to necrotic enteritis and coccidiosis likely increases with a thinner gut lining. Rapid digestion and great performance on pelleted diets is associated with a thinner gut lining. This doesn’t mean the bird is unhealthy, but, if exposed to an overload of bacteria, the bird could be more susceptible to succumbing to enteric diseases. Pelleted feed goes through a conditioning process where moisture and heat are added the combination of which is adequate to kill bacteria such as Salmonella.
Mash diets can have a positive impact on gut health over pellets or crumbles but only if the mash contains a variety of particle sizes. There has to be enough coarse particles to provide the benefit of stimulating the gastrointestinal tract, allowing for gizzard growth and slowing feed passage rate (Parsons et al, 2006; Mateos et al, 2012) as well as facilitating gut enzyme binding to feed particles by increasing the available surface area, thus aiding nutrient digestion and absorption (Svihus, 2011). Birds tend to have a thicker gut mucosal layer on mash than on pellets. An additional benefit in layers and breeders, who have adult digestive systems, is a slowing of feed intake (Leeson and Summers, 1997). Broilers eat a lot and need to get feed into them efficiently to allow them to grow at the rates determined by their incredible genetic potential. For layers and breeders it is actually preferable to slow consumption a bit. The level, type, and particle size of the fibre in feed ingredients, has more impact on the birds gut enzyme secretions than feed form will (Mateos et al, 2012). Manipulation of gut pH is virtually impossible using diet or feed form due to the huge buffering capacity of the gut microflora. Increased insoluble fibre in the diet will, over a period of days, influence the gut bacterial population make up but will have very little impact on gut pH.
Pellets and coarse particles are not mutually exclusive. A lot of broiler producers feed whole or coarsely cracked wheat with a crumbled supplement to get the best of both worlds: gut stimulation and great digestion and absorption. In addition, a pellet can also be made with coarsely ground grains in it. On the other side, specialized feed plants could have access to some newer techniques to heat treat mash diets to provide similar digestive benefits to the conditioning process in pelleted feeds in addition to chemical processes to sanitize mash feeds. Birds are highly adaptable and will get used to whichever feed texture you choose. Both have benefits depending upon the bird or the type of feeding system you use, and the rate of growth you wish to see. Keep in mind that young (0-10 days) birds of any strain do better on crumbled feeds to start with as their nutrient requirements are high and their digestive tracts are very naïve.
References:
Glover, B.G, J. M. Hadfield, J.W. Boney, K.L. Foltz, I. Holaskova, K.J. Ryan, and J.S. Moritz. 2018. Effects of Environment, Feed Form, and Caloric Density on Energy Partitioning, Subsequent Performance and immune response. J. Appl. Poult. Res. 27:507-521.
Leeson, S, and J. D. Summers. 1997. Commercial Poultry Nutrition, 2nd Edition. University Books, Guelph, ON.
Mateos, G.G., E. Jiménez-Moreno , M. P. Serrano , and R. P. Lázaro. 2012. Poultry response to high levels of dietary fiber sources varying in physical and chemical characteristics. J. appl. Poult. Res. 21 :156–174
Mckinney, L. J., and R. G. Teeter. 2004. Predicting effective caloric value of nonnutritive factors: I. pellet quality and II. Prediction of consequential formulation dead zones. Poultry Science 83:1165–1174.
Moritz, J. S., R. S. Beyer, K. J. Wilson, and K. R. Cramer. 2001. Effect of moisture addition at the mixer to a corn-soybean-based diet on broiler performance. J. Appl. Poult. Res. 10:347–353.Parsons, A.S., N.P. Buchanan, K.P. Blemings, M.E. Wilson, and J.S. Moritz. 2006. Effect of Corn Particle Size and Pellet Texture on Broiler Performance in the Growing Phase. J. Appl. Poult. Res.15: 245-255
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